The technology disclosed relates to accommodating embedded substrates during direct writing onto a workpiece such as a substrate or printed circuit board and to other patterning problems that benefit from an extended depth of focus. In particular, it relates to multi-focus direct writing of a workpiece by the continuous or step-wise movement of the workpiece during the sequence of exposures having different focus planes.
For several years, efforts have been under way to embed active and passive components in printed circuit substrates. The Japan Electronics Packaging and Circuits Association (JPCA), for instance, has published a series of standards related to device embedded substrates. E.g., JPCA-EB01—2nd Edition, Standard on Device Embedded Substrate—Terminology/Reliability/Design Guide (June 2009) (pp. 1-51).
Recently, the assignee of this patent began a pioneering introduction of a direct writer for patterning substrates. These inventors recognized a new problem associated with direct writing of substrates that does not seem to have been previously addressed. That is, embedded devices are relatively thick compared to normal traces on a substrate. When embedded devices are produced, the substrate becomes uneven, causing various complications.
Accordingly, an opportunity arises to introduce new direct writing technologies that compensate for unevenness of a substrate. Improved patterning flexibility and precision may result, in at least some implementations of the technology disclosed.